Preface: Xen is an open-source hypervisor that allows the simultaneous development, execution, and management of multiple virtual machines on one physical computer. Xen offers two types of virtualization: paravirtualization and full virtualization.

Background: XenServer is a Citrix product the company acquired from XenSource in 2007. Citrix’s XenServer provides 7 Network interface cards and 16 virtual disks.

The network I/O virtualization architecture in Xen can be a significant source of overhead for networking performance in guest domains. Xen provides each guest domain with a number of virtual network interfaces, which is used by the guest domain for all its network communications. Corresponding to each virtual interface in a guest domain, a `backend’ interface is created in the driver domain, which acts as the proxy for that virtual interface in the driver domain. All the backend interfaces in the driver domain (corresponding to the virtual interfaces) are connected to the physical NIC and to each other through a virtual network bridge.

Vulnerability details: The fix for XSA-423 added logic to Linux’es netback driver to deal with a frontend splitting a packet in a way such that not all of the headers would come in one piece. Unfortunately the logic introduced there didn’t account for the extreme case of the entire packet being split into as many pieces as permitted by the protocol, yet still being smaller than the area that’s specially dealt with to keep all (possible) headers together. Such an unusual packet would therefore trigger a buffer overrun in the driver.

Official announcement: For details, please refer to the link – https://xenbits.xenproject.org/xsa/advisory-423.html

Preface: Perhaps this isn’t the first time this year we’ve heard of Safari and iOS having design flaws. Since both elements are close to each other. It is inevitable that it may have an impact. In addition, Safari includes open source code. So when a design flaw is discovered, sometimes the results look similar. The reason is that it happens in the same component, but that component is composed of other open source software.

In accordance with Apple’s Vulnerability Management Policy. Due to commercial reasons, technical details are not disclosed. But if anyone is interested in what happened. Increases the difficulty of analysis. But no harm. Bold assumptions and careful verification are the definition of science.

Background: On iOS and related software operating system products (macOS and iPadOS), Safari is built into the operating system (OS). Furthermore, it uses Apple’s open source browser engine WebKit, which is derived from KHTML. WebKit is a browser engine developed by Apple and primarily used in its Safari web browser, as well as all web browsers on iOS and iPadOS. Removing Safari is not recommended as it may damage the operating system and cause your Apple device to malfunction. Technically, If you don’t use Safari, it doesn’t accumulate caches or other service files.

Vulnerability details: The issue was addressed with improved checks. This issue is fixed in Safari 16.6.1, macOS Ventura 13.6, OS 17.0.1 and iPadOS 17.0.1, iOS 16.7 and iPadOS 16.7. Processing web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited against versions of iOS before iOS 16.7.

My observation: Vendor not disclose the details, do you think point b will be trigger similar design weakness (processing web content may lead to arbitrary code execution)!

Universal links let users open your app when they tap links to your website within WKWebView and UIWebView views and Safari pages. The UIWebView uses UIKit framework while WKWebView uses WebKit. framework. in addition to links that result in a call to openURL:, such as those that occur in Mail, Messages, and other apps.

How to Creating and Uploading the Association File?

a.To create a secure connection between your website and your app, you establish a trust relationship between them. You establish this relationship in two parts:

i.An apple-app-site-association file that you add to your website

ii.A com.apple.developer.associated-domains entitlement that you add to your app

b.If your app runs in iOS 9 or later and you use HTTPS to serve the apple-app-site-association file, you can create a plain text file that uses the application/json MIME type and you don’t need to sign it.

Official announcement: Please refer to the following link for details –

https://nvd.nist.gov/vuln/detail/CVE-2023-41993

https://support.apple.com/en-us/HT213930

Preface: The Unbreakable Enterprise Kernel (UEK) is a Linux kernel built by Oracle and supported through Oracle Linux support.  Reliable Datagram Sockets (RDS) is a high-performance, low-latency, reliable, connectionless protocol for delivering datagrams. It is developed by Oracle Corporation. It was included in the Linux kernel 2.6.30 which was released on 9th of June, 2009.

Background: Based on TCP handshake definition: SYN > SYN/ACK > ACK: When the SYN is sent, the remote peer sends back a SYN/ACK. In traditional RDS module, syn-ack at this point would end up marking the conn as RDS_CONN_UP, and would again permit rds_send_xmi() threads through, so ideally we would synchronize on RDS_CONN_UP after lock_sock(), but cannot do that.

Because waiting on !RDS_IN_XMIT after lock_sock() may end up deadlocking with tcp_sendmsg(), and the RDS_IN_XMIT would not get set.

As a result, we set c_state to RDS_CONN_RESETTTING, to ensure that rds_tcp_state_change cannot mark rds_conn_path_up() in the window before lock_sock().

Vulnerability details: In the Unbreakable Enterprise Kernel (UEK), the RDS module in UEK has two setsockopt(2) options, RDS_CONN_RESET and RDS6_CONN_RESET, that are not re-entrant. A malicious local user with CAP_NET_ADMIN can use this to crash the kernel.

CVSS 3.1 Base Score 5.5

Official announcement: For details,please refer to the link – https://linux.oracle.com/cve/CVE-2023-22024.html

Preface: A Subject Alternate Name (or SAN) certificate is a digital security certificate which allows multiple hostnames to be protected by a single certificate. A SAN certificate may also be called a Unified Communication Certificate (or UCC), a multi-domain certificate, or an Exchange certificate.

A Subject Alternative Name (SAN) certificate is capable of supporting multiple domains and multiple host names with domains. SANS certificates are more flexible than Wildcard certificates since they are not limited to a single domain.

Vulnerability Description: An Allocation of Resources Without Limits or Throttling vulnerability in SUSE k3s allows attackers with access to K3s servers’ apiserver/supervisor port (TCP 6443) cause denial of service. This issue affects k3s: from v1.24.0 before v1.24.17+k3s1, from v1.25.0 before v1.25.13+k3s1, from v1.26.0 before v1.26.8+k3s1, from sev1.27.0 before v1.27.5+k3s1, from v1.28.0 before v1.28.1+k3s1.

Ref: An issue was found in K3s where an attacker with network access to K3s servers’ apiserver/supervisor port (TCP 6443) can force the TLS server to add entries to the certificate’s Subject Alternative Name (SAN) list, through a stuffing attack, until the certificate grows so large that it exceeds the maximum size allowed by TLS client implementations. OpenSSL for example will raise an excessive message size error when this occurs. No authentication is necessary to perform this attack, only the ability to perform a TLS handshake against the apiserver/supervisor port (TCP 6443).

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Upstream Security Advisories:

https://github.com/k3s-io/k3s/security/advisories/GHSA-m4hf-6vgr-75r2

SUSE information

Overall state of this security issue: Analysis

This issue is currently rated as having important severity.

Official announcement: For details, please refer to the link – https://nvd.nist.gov/vuln/detail/CVE-2023-32187

Preface: This vulnerability published on September 12, 2023. It had CVSS V3 base score 5.3. But based on the vulnerability details described, it seems it is unknown causes. But why does it happen?

Background: The GNU C Library project provides the core libraries for the GNU system and GNU/Linux systems, as well as many other systems that use Linux as the kernel. These libraries provide critical APIs including ISO C11, POSIX.1-2008, BSD, OS-specific APIs and more. These APIs include such foundational facilities as open, read, write, malloc, printf, getaddrinfo, dlopen, pthread_create, crypt, login, exit and more.

The Name Service Switch (NSS) configuration file, /etc/nsswitch[.]conf, is used by the GNU C Library to determine the sources from which to obtain name-service information in a range of categories, and in what order.

Vulnerability details: A flaw was found in glibc. In an extremely rare situation, the getaddrinfo function may access memory that has been freed, resulting in an application crash.

This issue is only exploitable when a NSS module implements only the _nss_*_gethostbyname2_r and _nss_*_getcanonname_r hooks without implementing the _nss_*_gethostbyname3_r hook.

The resolved name should return a large number of IPv6 and IPv4, and the call to the getaddrinfo function should have the AF_INET6 address family with AI_CANONNAME, AI_ALL and AI_V4MAPPED as flags.

Therefore, it triggers a use-after-free vulnerability.

What I added during my observation: When malloc hooks is enabled, then the hook pointers are set to the current default allocation functions. It is expected that if an app does intercept the allocation/free calls, it will eventually call the original hook function to do allocations.

Software developers have figured out why: For AF_INET6 lookup with AI_ALL | AI_V4MAPPED, gethosts gets called twice, once for a v6 lookup and second for a v4 lookup.  In this case, if the first call reallocates tmpbuf enough number of times, resulting in a malloc, th->h_name (that res->at->name refers to) ends up on a heap allocated storage in tmpbuf. Now if the second call to gethosts also causes the plugin callback to return NSS_STATUS_TRYAGAIN, tmpbuf will get freed, resulting in a UAF reference in res->at->name.  This then gets dereferenced in the getcanonname_r plugin call, resulting in the use after free.

Official announcement: For details, please refer to the link – https://nvd.nist.gov/vuln/detail/CVE-2023-4806

Preface: What is the difference between WebP and JPEG files? Both file types compress the image, making it easier to share and store. However, WebP files are typically much smaller than traditional JPEGs.

Background: Microsoft Edge (Chromium), it was first released in 2015 as the successor to Internet Explorer and is based on Google’s Chromium.
If the Chromium version of Edge isn’t available through Windows Update, you can install it manually using these steps:
1. Open Microsoft Edge download website.
2. Click the Download button.
3. Double-click the file to launch the wizard and install Microsoft Edge Chromium.

The following two components have a functional relationship required by Microsoft Edge.

WebP codec is a library to encode and decode images in WebP format. This package contains the library that can be used in other programs to add WebP support, as well as the command line tools ‘cwebp’ and ‘dwebp’ to compress and decompress images respectively.

What is WebView Windows 11? A web view control embeds a view into your app that renders web content using the Microsoft Edge Legacy rendering engine. Hyperlinks can also appear and function in a web view control. The WebView2 control is available as part of the Windows UI Library 3 (WinUI3).

Vulnerability details: Heap buffer overflow in WebP in Google Chrome prior to 116.0.5845.187 allowed a remote attacker to perform an out of bounds memory write via a crafted HTML page. (Chromium security severity: Critical)

Such design weakness was caused by a WebP code library (libwebp) heap buffer overflow weakness whose impact ranges from crashes to arbitrary code execution.

Remedy: The Stable and Extended stable channels has been updated to 116.0.5845.187 for Mac and Linux and 116.0.5845.187/.188 for Windows

Official announcement: Please refer to the link for details of Microsoft announcement –

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-4863

Preface: Ubuntu Server 22.04 ships with NVIDIA BlueField DPUs as commercial-grade Linux distribution with continuous OS and security updates. DOCA software is available on every leading operating system as a standalone package without a bundled OS for Arm® and x86 architectures.

Background: The NVIDIA cloud-native supercomputing platform leverages the NVIDIA BlueField DPU architecture with high-speed, low-latency. The DPU enables native cloud services that let multiple users securely share resources without loss in application performance. HPC and AI communication frameworks and libraries play a critical role in determining application performance. Due to their latency and bandwidth-sensitive nature, offloading the libraries from the host CPU or GPU to the BlueField DPU creates the highest degree of overlap for parallel progression of communication and computation.

Vulnerability details: NVIDIA ConnectX Host Firmware for the BlueField Data Processing Unit contains a vulnerability where a restricted host may cause an incorrect user management error. A successful exploit of this vulnerability may lead to escalation of privileges. 

CWE-286         Incorrect User Management

Official announcement: For details, please refer to the link –

https://nvidia.custhelp.com/app/answers/detail/a_id/5479

https://nvd.nist.gov/vuln/detail/CVE-2023-25519

Preface: Technicians tend to focus on zero-day vulnerability status. Makes sense. However, the computer world expands from workstations and intranets into the IoT world. The Internet of Things master put the workstation project into the IoT catalog early on. At the same time, software includes operating system platform and programming language design, and is not limited to Microsoft software product platforms. Therefore, any alleged vulnerability will be exploited by cybercriminals against real situations. Today, my focus in this brief topic is not on the severity of design flaws. The case was discovered in March last year. But there are still status updates today.

Background: The GNU C Library project provides the core libraries for the GNU system and GNU/Linux systems, as well as many other systems that use Linux as the kernel. These libraries provide critical APIs including ISO C11, POSIX.1-2008, BSD, OS-specific APIs and more. These APIs include such foundational facilities as open, read, write, malloc, printf, getaddrinfo, dlopen, pthread_create, crypt, login, exit and more.

The /etc/nsswitch[.] conf file is used to configure which services are to be used to determine information such as hostnames, password files, and group files.

The Name Service Switch (NSS) configuration file, /etc/nsswitch[.]conf, is used by the GNU C Library.

Vulnerability details: A flaw was found in glibc. In an uncommon situation, the gaih_inet function may use memory that has been freed, resulting in an application crash. This issue is only exploitable when the getaddrinfo function is called and the hosts database in /etc/nsswitch[.]conf is configured with SUCCESS=continue or SUCCESS=merge.

Official announcement: For details, please refer to the link – https://nvd.nist.gov/vuln/detail/CVE-2023-4813

Preface: Apple releases new iOS 15.7.9 and 16.6.1update for iPhone. iOS 15.7.9 and 16.6.1 like many of its predecessors, is a point upgrade and it patches up a security issue. But it doesn’t provides bug fixes technical details!

Background: The Core Graphics framework is based on the Quartz advanced drawing engine. It provides low-level, lightweight 2D rendering with unmatched output fidelity. You use this framework to handle path-based drawing, transformations, color management, offscreen rendering, patterns, gradients and shadings, image data management, image creation, and image masking, as well as PDF document creation, display, and parsing.

In macOS, Core Graphics also includes services for working with display hardware, low-level user input events, and the windowing system.

Vulnerability details: A buffer overflow issue was addressed with improved memory handling. This issue is fixed in macOS Monterey 12.6.9, macOS Big Sur 11.7.10, macOS Ventura 13.5.2, iOS 16.6.1 and iPadOS 16.6.1, iOS 15.7.9 and iPadOS 15.7.9. Processing a maliciously crafted image may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited.

My speculation about this vulnerability: I observe that design weakness might happens when Quartz handle the CGdata. What is Quartz? The Core Graphics framework is based on the Quartz advanced drawing engine. Quartz handle path-based drawing, antialiased rendering, gradients, images, color management, PDF documents, and more.

When the CGDataProvider is finished using the memory buffer, it will call the routine pointer, giving your application the opportunity to release that buffer. In addition to the routine pointer, CGDataProviderCreateWithData accepts a pointer value that the computer will pass to the routine. If your application does not want to use the routine pointer, you can simply pass NULL for both of these parameters.

However, core services itself have the following guideline. after you’re finished with buffers that have have their own memory allocation, it’s important that you free the memory allocated to them:

sourceBuffer[.]free() destinationBuffer[.]free()

So, whether the weakness happen in this function. Refer to point 5 and 6 in attached diagram? Since the core service (point 6) buffer require define syntax to clear up. If not defined, a buffer overflow issue might occur!

Ref: There are a number of services in the operating system that can return CGImages to your application. The most obvious source is Core Graphics, which offers a number of routines for creating CGImages from various data sources. However, in addition to Quartz, you can obtain CGImages from other operating system services. For example, QuickTime provides the routine GraphicsImportCreateCGImage, which can create a CGImage from a QuickTime Graphics importer.

Official announcement: For details, please refer to the link – https://nvd.nist.gov/vuln/detail/CVE-2023-41064

Preface: When technology world relies on cloud computing. Meanwhile fast switching includes high speed backbone will be counted. The technology shift physical network device go to virtual computing platform. That said, the traditional design goal one software installs to one hardware unit. For instance, a single operating system install on one hardware device has been change. The actual example are Cumulus Linux and Cisco IOS. Both are major players in cloud computing network switching technology.

Background: VXLAN is an encapsulation protocol that provides data center connectivity using tunneling to stretch Layer 2 connections over an underlying Layer 3 network. The VXLAN encapsulation mechanism encapsulates the IPv6 packets in the overlay as IPv4 UDP packets and uses IPv4 routing to transport the VXLAN encapsulated traffic. A switch virtual interfaces (SVI) or VLAN interface, is a virtual routed interface that connects a VLAN on the device to the Layer 3 router engine on the same device.

Remark: Virtual routing and forwarding (VRF) is an IP-based computer network technology that enables the simultaneous co-existence of multiple virtual routers (VRs) as instances or virtual router instances (VRIs) within the same router.

Vulnerability details: NVIDIA Cumulus Linux contains a vulnerability in forwarding where a VxLAN-encapsulated IPv6 packet received on the SVI interface with DMAC/DIPv6 set to the link-local address of the SVI interface may be incorrectly forwarded. A successful exploit may lead to information disclosure.

My observation: The inner IPv4/IPv6 packet is not really bound to any receiving interface and thus the End.DT4/DT6 sets the VRF (associated with the corresponding routing table) as the *receiving* interface. In other words, the End.DT4/DT6 processes a packet as if it has been received directly by the VRF (and not by one of its slave devices, if any). In this way, the VRF interface is used for routing the IPv4/IPv6 packet in according to the routing table configured by the End.DT4/DT6 instance.

*Vendors publish design limitations. But the impact could go beyond information leakage?

Official announcement: For details, please refer to the link – https://nvidia.custhelp.com/app/answers/detail/a_id/5480